staging: csr: remove unneeded call to memset().

In uf_send_pkt_to_encrypt(), the memory area zeroed by this call to memset() is
overwritten by a call to memcpy() a few instructions later, so it is not needed.

Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>